One of the many questions we receive in feedback on our annual Future Watch issue, now available on newsstands and in the THN.com store, is what constitutes a prospect. Why are some players included in the team’s top 10 rankings and others left off?

Even though we have a 50-game rule – if you’ve played 50 NHL games when we start the Future Watch process, you’re no longer a prospect, you’re an NHLer – we often break that rule on a case-by-case basis.

Rookies who have made an NHL lineup right from the start of the season are naturally omitted. Taylor Hall and Jeff Skinner are obvious examples. Even though they were well under the 50-game mark when we started putting Future Watch together in January, there’s no doubt they established themselves as NHLers.

We also bend that rule when it comes to young players who spent a previous season in the NHL – and surpassed the 50-game mark – but started this season in the minors. Mikkel Boedker is the poster boy. He was rushed to the NHL as an 18-year-old in 2008-09 and played 78 games with Phoenix. Demoted to the American League last season, he placed 14th on our top 50 ranking. This year, he moved up to ninth and is still held in high esteem by the scouting community.

Those players are the easy exceptions to make. Others are more difficult. The Future Watch top 50 ranking takes about a month to put together because it involves a lot of back and forth communication with NHL scouts, who provide us with the expertise in this project.

Some young players were left off the prospect list because they were starting to play regularly in the NHL and projected to stay there the rest of the season. Such examples are Anaheim’s Brandon McMillan, Boston’s Adam McQuaid, New Jersey’s Mattias Tedenby and Travis Hamonic of the Islanders.

Others prospects fell to the other side of that bubble. They were playing in the NHL, but not regularly in a lot of cases and we projected them to be candidates for demotion, due to either numbers or another player returning from injury. We included these players in Future Watch. Examples are Atlanta’s Patrice Cormier, Buffalo’s Luke Adam, Carolina’s Zac Dalpe and Edmonton’s Jeff Petry.

In some cases, we were wrong about prospects being up in the NHL for just a cup of coffee. Some “bubble” players in January have become valued regulars in the NHL by March. So you might be surprised to see them still ranked in Future Watch. Examples are Chicago’s Nick Leddy, Columbus’ Matt Calvert, Florida’s Keaton Ellerby and Toronto’s James Reimer. They’re clearly in the NHL to stay.

A surprising number of other prospects ranked in Future Watch have already made it to the NHL, in the past few weeks alone: Dustin Jeffrey in Pittsburgh, Keith Aulie of Toronto and Chris Tanev of Vancouver, for example.

The cover boy for this year’s Future Watch, which also issues grades and rankings for each team’s list of prospects and 21-and-under NHLers, is Los Angeles’ Brayden Schenn. The Saskatoon Blades center finished way ahead of the competition in our top 50 ranking, gaining 11 first-place votes from our 18-scout panel. He won’t make an NHL impact this season, but is already a Calder Trophy favorite for 2011-12.

Brian Costello is The Hockey News’s senior special editions editor and a regular contributor to THN.com with his blog. For more great profiles, news and views from the world of hockey, subscribe to The Hockey News magazine.